scholarly journals Ion Binding Properties of a Naturally Occurring Metalloantibody

Antibodies ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 10
Author(s):  
Elinaz Farokhi ◽  
Jonathan K. Fleming ◽  
M. Frank Erasmus ◽  
Aaron D. Ward ◽  
Yunjin Wu ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Bound State ◽  
Biologically Active ◽  
Titration Calorimetry ◽  
Fab Fragment ◽  
Inductively Coupled ◽  
Flame Atomic Absorption ◽  
Naturally Occurring ◽  
Sphingosine 1 Phosphate ◽  
Plasma Mass Spectrometry

LT1009 is a humanized version of murine LT1002 IgG1 that employs two bridging Ca2+ ions to bind its antigen, the biologically active lipid sphingosine-1-phosphate (S1P). We crystallized and determined the X-ray crystal structure of the LT1009 Fab fragment in 10 mM CaCl2 and found that it binds two Ca2+ in a manner similar to its antigen-bound state. Flame atomic absorption spectroscopy (FAAS) confirmed that murine LT1002 also binds Ca2+ in solution and inductively-coupled plasma-mass spectrometry (ICP-MS) revealed that, although Ca2+ is preferred, LT1002 can bind Mg2+ and, to much lesser extent, Ba2+. Isothermal titration calorimetry (ITC) indicated that LT1002 binds two Ca2+ ions endothermically with a measured dissociation constant (KD) of 171 μM. Protein and genome sequence analyses suggested that LT1002 is representative of a small class of confirmed and potential metalloantibodies and that Ca2+ binding is likely encoded for in germline variable chain genes. To test this hypothesis, we engineered, expressed, and purified a Fab fragment consisting of naïve murine germline-encoded light and heavy chain genes from which LT1002 is derived and observed that it binds Ca2+ in solution. We propose that LT1002 is representative of a class of naturally occurring metalloantibodies that are evolutionarily conserved across diverse mammalian genomes.

scholarly journals Optimized Simultaneous Determination of Several Elements in Human Intestinal Caco-2 TC7 Cells by Inductively Coupled Plasma-Mass Spectrometry after Closed Vessel Microwave Digestion

2003 ◽  
Vol 86 (6) ◽  
pp. 1225-1231 ◽  
Author(s):  
Laurent Noël ◽  
Thierry Guérin ◽  
Jean-Marc Frémy ◽  
Hélène Huet ◽  
Martine Kolf-Clauw
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Certified Reference Materials ◽  
Microwave Digestion ◽  
Absorption Spectrometry ◽  
Inductively Coupled ◽  
Flame Atomic Absorption ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

Abstract A rapid procedure, based on closed vessels microwave digestion and inductively coupled plasma-mass spectrometry (ICP-MS), was evaluated to ascertain the effect of chronic exposure to cadmium on intracellular accumulation of minor and essential trace elements in cultured epithelial cells (Caco-2 TC7). For all measurements, the method of external calibration was used and 3 elements (Be, Sc, In) were selected as internal standards. Optimization procedures are discussed and results are presented for the total determination of 9 key analytes (Na, Mg, Ca, Cr, Mn, Cu, Zn, Mo, and Cd) in certified reference materials (CRMs) and 20 samples of Caco-2 TC7 cells long-term exposed to Cd. The performance characteristics of the analytical system were evaluated by calibration and linearity, limits of detection and quantitation, accuracy with spiking, trueness and repeatability with available CRMs. As a complement to the ICP-MS determinations, both available CRMs and cell samples were analyzed either by electro thermal-or flame atomic absorption spectrometry. The results were in good agreement with the ICP-MS results.

scholarly journals Geochemistry of Groundwater and Naturally Occurring Biogenic Pyrite in the Holocene Fluvial Aquifers in Uphapee Watershed, Macon County, Alabama

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 912
Author(s):  
Md Mahfujur Rahman ◽  
Ming-Kuo Lee ◽  
Ashraf Uddin
Keyword(s):  
Trace Elements ◽  
Sulfate Reduction ◽  
Inductively Coupled Plasma ◽  
Sem Analysis ◽  
Flow Path ◽  
Sulfate Reducing ◽  
Inductively Coupled ◽  
Drinking Water Standard ◽  
Naturally Occurring ◽  
Plasma Mass Spectrometry

Naturally occurring biogenic pyrite has been found in Holocene fluvial aquifers in the Uphapee watershed, Macon County, Alabama. The electron microprobe (EMP) analysis showed that the pyrite grains contain 0.20–0.92 weight% of arsenic (As). The scanning electron microscope and energy dispersive spectroscopy (SEM-EDS) analysis confirmed a similar concentration of As in the pyrite that was consistent with the EMP analysis. The SEM analysis also confirmed the presence of additional trace elements such as cobalt (0.19 wt.%), and nickel (0.15 wt.%), indicative of pyrite’s capacity to sequester As and other trace elements. Pyrite grains were naturally formed and developed as large (20–200 μm) euhedral (i.e., cube, octahedron) crystals and non-framboid aggregates. However, the inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the As concentration in the groundwater was not high, and it was within the EPA drinking water standard for As (10 µg/L). These results indicate that dissolved As is sequestered in naturally formed pyrite found in the fluvial sediments. The groundwater was moderately reducing to slightly oxidizing (Eh = 46 to173 mV), and nearly neutral to slightly acidic (pH = 5.53 to 6.51). Groundwater geochemistry data indicated a redox sequence of oxidation, denitrification, Mn(IV) reduction, Fe(III) reduction, and sulfate reduction along the flow path in the fluvial aquifer. The downgradient increases in dissolved Mn and then Fe concentrations reflect increased Mn(II) and Fe(II) production via microbial competition as the aquifer becomes progressively more reduced. Bacterial sulfate reduction seems to dominate near the end of the groundwater flow path, as the availability of Mn- and Fe-oxyhydroxides becomes limited in sediments rich in lignitic wood where increasing sulfate reduction leads to the formation of biogenic pyrite. The groundwater is a Ca-SO4 type and is not SO4 limited; thus, sulfate may serve as an electron acceptor for the bacterial sulfate-reducing reactions that sequester As into pyrite, which in turn results in very low groundwater As concentration (<2 µg/L).

scholarly journals Development of New Canned Chub Mackerel Products Incorporating Edible Seaweeds—Influence on the Minerals and Trace Elements Composition

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1133
Author(s):  
Elsa F. Vieira ◽  
Cristina Soares ◽  
Susana Machado ◽  
M. Teresa Oliva-Teles ◽  
Manuela Correia ◽  
...  
Keyword(s):  
Trace Elements ◽  
Inductively Coupled Plasma ◽  
Absorption Spectrometry ◽  
Chub Mackerel ◽  
Continuum Source ◽  
Inductively Coupled ◽  
Flame Atomic Absorption ◽  
Edible Seaweeds ◽  
Saccorhiza Polyschides ◽  
Plasma Mass Spectrometry

This study aimed to develop new canned chub mackerel products incorporating edible seaweeds (Ascophyllum nodosum, Fucus spiralis, Saccorhiza polyschides, Chondrus crispus, Porphyra sp. and Ulva sp.) harvested in the Portuguese North-Central coast, with simultaneous sensory improvement and minerals enrichment. Two processes were compared, namely the addition of seaweeds in i) the canning step and ii) in the brining step (as the replacement for salt). The concentrations of four macrominerals (Na, K, Ca and Mg), chloride, and twelve trace elements (Co, Cu, Fe, I, Li, Mn, Mo, Rb, Se, Sr, V and Zn) were determined by high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. Results showed that canned chub mackerel incorporating C. crispus and F. spiralis was found to be the preferred sensory option, also exhibiting contents enriched with Cl, Co, Cu, Fe, I, Li, Mg, Mn, Mo, Na, Rb, Se, and Sr. This effect was more pronounced when both seaweed species were added to replace the salt added in the brining step.

scholarly journals Zinc-independent activation of Toll-like receptor 4 by S100A9

2019 ◽  
Author(s):  
Andrea N. Loes ◽  
Ran Shi ◽  
Michael J. Harms
Keyword(s):  
Inductively Coupled Plasma ◽  
Site Directed Mutagenesis ◽  
Titration Calorimetry ◽  
Functional Assay ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
A Cell

ABSTRACTThe homodimer formed by the protein S100A9 induces inflammation through Toll-like receptor 4 (TLR4), playing critical roles in both healthy and pathological innate immune responses. The molecular mechanism by which S100A9 activates TLR4 remains unknown. Previously, the interaction between purified S100A9 and TLR4 was shown to depend on Zn2+; however, the Zn2+ binding site(s) on S100A9 were not identified. Here, we investigated the role of Zn2+ binding in the pro-inflammatory activity of S100A9. We found that the S100A9 homodimer was prone to reversible, Zn2+-dependent aggregation in vitro. Using a combination of site-directed mutagenesis and Isothermal Titration Calorimetry (ITC), we identified multiple residues that contribute to Zn2+ binding in S100A9. We then used mutagenesis to construct a version of S100A9 with no detectable Zn2+ binding by either ITC or Inductively Coupled Plasma-Mass Spectrometry. This protein did not exhibit aggregation upon addition of saturating Zn2+. Further, despite the lack of Zn2+-binding, this protein was capable of activating TLR4 in a cell-based functional assay. We then modified the functional assay so the Zn2+ concentration was exceedingly low relative to the concentration of S100A9 added. Again, S100A9 was able to activate TLR4. This reveals that, despite the ability of S100A9 to bind Zn2+, S100A9 does not require Zn2+ to activate TLR4. Our work represents an important step in clarifying the nature of the interaction between S100A9 and TLR4.

Sign in / Sign up

Export Citation Format

Share Document